Simpler than that: It just displays the data in 60-second chunks, delayed by sixty seconds. Here's one of the blocks:

http://glow.mozilla.org/data/json/2011/03/22/16/51/map.json

This would actually be an excellent opportunity for http streaming (ie, the forever frame), too. Long polling is great when you're waiting for a singular event, but not so much when it's ongoing data being pushed down.